500: Lagoon 500 Nearly Sunk

[Lagoon4us]

You must really frustrate people around you with an attitude such as you display here, Minaret Lagoons are built very similar to each other if you can show me where i said this boat could not have sunk then please do.

I'll bet a beer the volumes at the ends of a 50 have enough reserve bouyancy to keep it afloat with all reservations previously given.

In this case the leg ripped out, in this case the water flowed into the midship space, If the limber holes were plugged maybe this may not have happened?

Maybe the damage extended into the midship area ie past the watertight between engine and accommodation?

My point stands and i was surprised it was the case, it appears on a 440 at least the water tights volumes ie flotation are equal or better than the wetted weight AS IT SHOULD BE!!!!! Your issue seems to be that i FELT a 50 may be the same..

Cheers

[minaret]

Originally Posted by Lagoon4us

You must really frustrate people around you with an attitude such as you display here, Minaret Lagoons are built very similar to each other if you can show me where i said this boat could not have sunk then please do.

I'll bet a beer the volumes at the ends of a 50 have enough reserve bouyancy to keep it afloat with all reservations previously given.

In this case the leg ripped out, in this case the water flowed into the midship space, If the limber holes were plugged maybe this may not have happened?

Maybe the damage extended into the midship area ie past the watertight between engine and accommodation?

My point stands and i was surprised it was the case, it appears on a 440 at least the water tights volumes ie flotation are equal or better than the wetted weight AS IT SHOULD BE!!!!! Your issue seems to be that i FELT a 50 may be the same..

Cheers

Yep, that would be my issue. Thought that was pretty clear.


My other issue would be that this info should be put out there by Lagoon. But it's not. In fact, when they were ordered by a court to do so, they refused. Which leaves us making assumptions based on the "feeling" of owners if different models of Lagoon. Less than ideal. And very suspicious in my book. What do they have to hide? Something, obviously.

[neilpride]

Please check the survey pictures about the bulkheads at the top deck level, is not just the dam limber hole, is the gooo around corners and other flaws in the bulkhead construction, at the top where the bulkhead meet the deck , remember Titanic??

[colemj]

Plexus was used on our boat for several things (not bulkheads) and I have a hard time believing that it is weaker than polyester resin. That stuff seems indestructible to me, and I wish it would crack off on a couple of things that I can't remove now. Many boat's hull-deck joints are installed with Plexus and these are considered monocoques constructions after.

Mark

[neilpride]

Originally Posted by colemj

Plexus was used on our boat for several things (not bulkheads) and I have a hard time believing that it is weaker than polyester resin. That stuff seems indestructible to me, and I wish it would crack off on a couple of things that I can't remove now. Many boat's hull-deck joints are installed with Plexus and these are considered monocoques constructions after.

Mark

There is no boats with hull to deck joint made with Plexus, pls point a example, the norm this days is called 5200, a example is a HR who got the deck joint glassed inside, and a proper bulkhead atatchment is made with FG all around, now like some beneteaus or other production boats using a pan liner or grid to acomodate part of the bulkhead , Plexus is used, same for gluing the liner to the hull, and is not indestructible, it break, is hard.. mounting a bulkhead with just Plexus around is insane ...ask Minaret...

[colemj]

J-Boat is an example of current sailboats that use Plexus for the hull-deck joint. Alerion is another. So is Southerly, as well as Mystery (Cornish Crabber), Sunday and C&C. Many high-end, but small production racing boats like the Akilaria 40 use it for this purpose. Ocean Yachts, Formula, Donzi and Baja are powerboats that use it there.

In fact, there are so many using it for bonding decks to hulls that I feel silly answering your question. I gave you 11 companies using it in their production lines for this purpose, and the list is far larger than that. Aren't you the one working in the marine industry?

5200 is a different beast altogether. While that is a good adhesive as well as a sealant, it is flexible and requires glassing over it. Plexus is a solid bonding product that is stiff and not a sealant in any way. The fiberglass it is bonded to will fail before the Plexus does.

Mark

[robert sailor]

What are the real production builders using for hull to deck joints these days??

[minaret]

Originally Posted by colemj

J-Boat is an example of current sailboats that use Plexus for the hull-deck joint. Alerion is another. So is Southerly, as well as Mystery (Cornish Crabber), Sunday and C&C. Many high-end, but small production racing boats like the Akilaria 40 use it for this purpose. Ocean Yachts, Formula, Donzi and Baja are powerboats that use it there.

In fact, there are so many using it for bonding decks to hulls that I feel silly answering your question. I gave you 11 companies using it in their production lines for this purpose, and the list is far larger than that. Aren't you the one working in the marine industry?

5200 is a different beast altogether. While that is a good adhesive as well as a sealant, it is flexible and requires glassing over it. Plexus is a solid bonding product that is stiff and not a sealant in any way. The fiberglass it is bonded to will fail before the Plexus does.

Mark

Having done a lot of destructive testing on Plexus, I would mostly agree with that assessment. The problem with Plexus is when you try to bridge gaps with it. As long as joints are tight, it's awesome. But it's also pretty brittle, very little flex. When joints aren't great and they try to bridge gap with it (common), it tends to crack after a lot of load cycling. I see a lot of this in jet skis, which are generally built with Plexus or cross linked hot glue. The latter is the more modern choice, because a lot of failures were seen with Plexus in this particular high load cycle application. Just cause its "monocoque" construction when new doesn't mean it will continue to be so after a lot of high load cycles (cats are good at developing those). This is why glass tabs will always be better than bonding, they're strong AND flexible. And a boat flexes (especially a cat). Just because lots of builders use it doesn't mean it's the best way, quite the opposite. Just means it makes the builders the most profit with acceptable risk. Which is then minimized by the business practices we see here.

[Gpolar]

I was surprise that sailboat do not have real water tight compartment. Maybe to expensive or too heavy to build?

[colemj]

Originally Posted by robert sailor

What are the real production builders using for hull to deck joints these days??

J-Boat, Alerion, Southerly and C&C are not real production builders? Neither are Formula, Donzi and Baja? And manufacturers that don't churn out 100's of boats each year aren't "real"?

Mark

[robert sailor]

I understand that your list included production builders and some good ones at that but I wanted to know what the high production guys were using Beneteau, Bavaria, etc.

[colemj]

Originally Posted by minaret

Having done a lot of destructive testing on Plexus, I would mostly agree with that assessment. The problem with Plexus is when you try to bridge gaps with it. As long as joints are tight, it's awesome. But it's also pretty brittle, very little flex. When joints aren't great and they try to bridge gap with it (common), it tends to crack after a lot of load cycling. I see a lot of this in jet skis, which are generally built with Plexus or cross linked hot glue. The latter is the more modern choice, because a lot of failures were seen with Plexus in this particular high load cycle application. Just cause its "monocoque" construction when new doesn't mean it will continue to be so after a lot of high load cycles (cats are good at developing those). This is why glass tabs will always be better than bonding, they're strong AND flexible. And a boat flexes (especially a cat). Just because lots of builders use it doesn't mean it's the best way, quite the opposite. Just means it makes the builders the most profit with acceptable risk. Which is then minimized by the business practices we see here.

I wasn't commenting on it's performance or applicability - just naming boats that use it for bonding hulls to decks since neilpride seemed unaware of that usage. I don't hear of many J-boat deck joints failing. Nor do the racing boats driving hard into heavy seas report many failings. It is hard to believe the cost differential of using Plexus and bolts is that much cheaper than sealant caulk, bolts and glass tabbing. Nor do I believe Plexus and bolt construction flexes enough to fail regularly, if at all. I would need data showing Plexus and bolt construction is weaker than fiberglass tabbing, let alone simply using sealant caulking and bolts without any tabbing, which many (most?) boats use.

Mark

[minaret]

Originally Posted by colemj

I wasn't commenting on it's performance or applicability - just naming boats that use it for bonding hulls to decks since neilpride seemed unaware of that usage. I don't hear of many J-boat deck joints failing. Nor do the racing boats driving hard into heavy seas report many failings. It is hard to believe the cost differential of using Plexus and bolts is that much cheaper than sealant caulk, bolts and glass tabbing. Nor do I believe Plexus and bolt construction flexes enough to fail regularly, if at all. I would need data showing Plexus and bolt construction is weaker than fiberglass tabbing, let alone simply using sealant caulking and bolts without any tabbing, which many (most?) boats use.

Mark

You are talking deck joints. I think Neil was talking bulkheads and liners.

The cost differential is massive. You are replacing a full glass crew which needs many hours to properly do its job with one man with a pneumatic gun and mixing wands. No prep, no clean up. No experience required. Astronomical savings for the builder.

[colemj]

Neil asked me specifically for an example of a manufacturer that uses Plexus for hull-deck joint bond.

Cost reduction is a valid reason to change methods, as long as the method is valid. I maintain that Plexus and bolt deck joints are as valid as 5200, bolt and glass tabbed joints. It is certainly more valid than sealant caulk and bolts only, which is a very common technique.

Mark

[neilpride]

I own a 40 C&C some years agoo, pls give me a link where we can see C&c is using this days plexus for a hull to deck joint, quite curious as the hull to deck joint flex and plexus dont, C&C use butyl tape in the early days for hull to deck joint same for deck hardware and hatches, Plexus as far i know is used for liners and grid gluing to the hull and bulkheads, a link will be nice...